The present invention relates to a steel structure including pre-stressing brackets for improving load-carrying capacity and serviceability thereof, and more particularly, to a steel structure including pre-stressing brackets for improving load-bearing capacity and use performance thereof wherein the connecting brackets are spaced apart from each other between a steel girder and a cover plate to prevent the installation of the cover plate from being limited by the connection portions of the neighboring steel girders, thereby allowing prestressing ranges to be continuously introduced to increase the prestressing effects, and the steel girder and the cover plate are spaced apart from each other by means of the formation of the connecting brackets, thereby increasing moment of inertia of section and optimizing section efficiency to provide a bridge for long span.
Generally, a steel girder is formed of an H-beam or I-beam and is adapted to be connected to piers or abutments of a bridge to constitute the upper structure of the bridge. In this case, the steel girder is made to a standard given size, that is, to a size of roughly 13 m to 15 m for the easiness of the manufacturing, carrying, and installing work thereof.
So as to allow the steel girders made to a given standard size to be used for long span, they are connected to each other, and thus, a connection portion should be formed on the end portions of the neighboring steel girders.
In this case, a steel plate is provided on the web and flanges formed on the end portion of each steel girder to allow the steel girders to be coupled to each other, and to do this, the steel plate and the web and flanges have the corresponding coupling holes to each other.
Thus, high tension bolts are inserted into their coupling holes and are fastened with nuts, thereby coupling the web and the steel plate and also coupling the flanges and the steel plate.
Accordingly, a thermal prestressing cover plate is covered fixedly on the connection portion of the steel girders used for long span, especially on the underside surface of the flange of each steel girder.
Because of the connection portion where the high tension bolts are fastened to connect the flange and the steel plate, at this time, it is hard to continuously cover the cover plates onto the steel girders.
The connection portion between the neighboring steel girders restricts and limits the continuous installation of the cover plates to cause the prestressing range caused by the cover plate to be limited to a size of 13 m to 15 m, so that the prestressing ranges are intermittently introduced to reduce the prestressing effects generated from the cover plate.
Furthermore, if the cover plate is connected directly to the steel girder in the conventional practice, the stiffness of the section caused by the moment of inertia of section is limited to the height of the steel girder, which causes the load-bearing capacity to be undesirably lowered, thereby making it impossible to be applicable to the bridge for long span.